KU1 Quartz Research Articles

Оптические и фотолюминесцентные свойства тонкой пленки оксида цинка на подложке из тантала лития

Presents the results of the study of the structural, optical and photo luminescent properties of the thin films ZnO on LiNbO3 substrate. The results of X-ray structural analysis of a zinc oxide film synthesized on a single-crystal LiTaO3 substrate and on a KU-1 quartz substrate are presented. Present the transmission spectra, reflection spectra and the spectral dependence of zinc oxide thin films on substrate LiTaO3 and the structure of ZnO-SiO2 in the ultraviolet and visible spectral ranges.

Optical and photoluminescent properties of the thin film zinc oxide on the LiTaO-=SUB=-3-=/SUB=- substrate

Presents the results of the study of the structural, optical and photo luminescent properties of the thin films ZnO on LiNbO3 substrate. The results of X-ray structural analysis of a zinc oxide film synthesized on a single-crystal LiTaO3 substrate and on a KU-1 quartz substrate are presented. Present the transmission spectra, reflection spectra and the spectral dependence of zinc oxide thin films on substrate LiTaO3 and the structure of ZnO-SiO2 in the ultraviolet and visible spectral ranges. Keywords:zinc oxide, laser ablation, ferroelectric materials, X-ray structural analysis, atomic-force microscopy surface, photoconductivity, method Tikhonov-Lavrentiev regularization.

Structural and photoelectric properties the thin film ZnO on LiTaO-=SUB=-3-=/SUB=- substrate

The results of the study of the structural and photoelectric properties of the ZnO-LiTaO3 thin-film structure are presented. The results X-ray structural analysis and results atomic-force microscopy of the surface zinc oxide thin films synthesized on a single-crystal lithium tantalite substrate and on a KU-1 quartz substrate are presented. The spectral dependence of photoconductivity in the thin film structure of ZnO-LiTaO3 and the structure of ZnO-quartz in the ultraviolet and visible spectral ranges are presented. Keywords: zinc oxide, laser ablation, ferroelectric materials, X-ray structural analysis, atomic-force microscopy surface, photoconductivity, method Tikhonov-Lavrentiev regularization.

Radiation hardening and optical properties of materials based on SiO2

Preliminary studies have shown that the optical absorption spectra of radiation-colored glasses correspond to the spectral behavior of the scattering losses of an optically inhomogeneous medium. The reasons for the same optical changes in glasses of different compositions are the radiation-induced electric charge separation in the structurally nano-inhomogeneous glass volume, polarization and formation of nanometer optical inhomogeneities. The authors of this work prove that the radiation changes in the mechanical and optical properties of silicate glasses are of the same nature. The performed estimates indicate that the electric charge separation in the glasses occurs up to absorbed doses of about 1 MGy. The local electric charge separation due to the appearance of Coulomb forces leads to radiation hardening of the glasses. The estimated Coulomb hardening of the quartz glasses was ~ 107 Pa. The theoretical results were experimentally confirmed by measuring the mechanical properties of the glasses under high intensity proton irradiation as well as by testing the mechanical strength of a composite material based on quartz glass. Under proton irradiation with a dose rate of 5×103 Gy/s (energy of 8 MeV) up to threshold doses of ~ (1 – 5) ×106 Gy in the KU-1 quartz glasses, the decrement of acoustic vibrations decreased due to Coulomb hardening. After gamma irradiation with 1.34×105 Gy, the tensile strength of the composite material based on quartz glass increased by up to 20 MPa. This value is in the range of estimates of Coulomb hardening of quartz glasses. It is also shown that ionizing radiation does not affect the elastic modulus of materials based on SiO2.

Cherenkov radiation and cathodoluminescence in sapphire, quartz, and diamond under the excitation of an electron beam

The paper reports data on the emission of sapphire, KU-1 quartz, and synthetic diamond in the wavelength range of 200–800 nm excited by a pulsed electron beam with an energy of up to 350 keV. Broadband radiation, the intensity of which increases with decreasing wavelength in the range of 220–400 nm, was detected. Such dependence of the radiation intensity on the wavelength is characteristic of Cherenkov radiation (CR). Moreover, the duration of the radiation pulse coincides with that of the electron beam current pulse. For sapphire and quartz, the duration of radiation pulses at the spectral range 220–400 nm is close to the duration to electron beam current pulses. For synthetic diamonds, both cathodoluminescence and CR are detected in this spectral region. The intense band of free excitons with maximum at 235 nm is found at high beam current densities and electron energies 50–350 keV.

Фотолюминесцентные и фотоэлектрические свойства тонкопленочной структуры ZnO-LiNbO-=SUB=-3-=/SUB=- в ультрафиолетовом и видимом диапазонах спектра

In article are presebted the results of study the structural, optical, photoluminescent and photoelectric properties structure of the layer thin-film ZnO on the monocrystal LiNbO3 substrate. Presents the results of X-ray structural analysis of a zinc oxide thin film synthesized on a single-crystal lithium niobate substrate and on a KU-1 quartz substrate are presented. Are presented the results investigations of transmission spectra, reflection spectra and absorption spectra in the ultraviolet and visible spectral range. Are presented investigations spectral dependence of photoluminescence and the spectral dependence of the photoconductivity currents in the thin film structure of ZnO-LiNbO3 and the structure of ZnO-SiO2 in the ultraviolet and visible spectral range.

Emission of diamonds, leucosapphire, and KU-1 quartz in the range of 200–800 nm excited by electron beams with a pulse duration of 0.5 and 12 ns

The paper presents the results of Cherenkov radiation (CR) studies in various crystals excited by nanosecond and subnanosecond electron beams with an electron energy of up to 400 and 200 keV, respectively. These studies are motivated by the need to develop and create calibrated sensors of runaway electrons for tokamak-type installations. The spectral and amplitude-time characteristics of the radiation of different specimens of diamonds, leucosapphire, and KU-1 quartz excited by the electron beams were obtained and compared. These crystals were chosen on the basis of their transparency in the ultraviolet region of the spectrum. CR was observed with a spectrometer. An increase in the radiation energy with decreasing wavelength was observed in synthetic diamonds of IIa type, leucosapphire, and KU-1 quartz. The amplitude-time characteristics of the radiation of crystals, including CR, were measured with a photodiode having a pulse response time of up to ≈80 ps. In chemical vapor deposited high purity diamonds excited by both nanosecond and subnanosecond beams, an exciton radiation with a maximum at 235 nm was observed. Results show that leucosapphire and quartz can be used to create detectors of electrons with energies above 200 keV.

Cherenkov Radiation in the Visible and Ultraviolet Spectral Ranges from 6-MeV Electrons Passing through a Quartz Plate

Cherenkov radiation and pulsed cathodoluminescence spectra in the ultraviolet, visible, and near infrared regions generated by a 6-MeV electron beam passing through GE-014 and KU1 quartz plates have been experimentally studied. The Cherenkov radiation spectrum has been recorded in the ultraviolet and visible regions and its change is shown at the variation of the angle between the plane of the plate and the direction of the electron beam. The data on the conditions of recording of the Cherenkov radiation spectra at the excitation of plane-parallel plates of quartz, sapphire, and diamond have been presented. It has been shown that the total internal reflection in the crystals with a high refractive index imposes certain conditions on the geometry of the output of Cherenkov radiation into vacuum at electron energies above 500 kev.

Infrared Spectra of KU1 and KS-4V Quartz Glass Irradiated by Fast Neutrons

IR absorption spectra of quartz glass with varying contents of hydroxyl OH groups, namely, KU1 (1000 ppm OH) and KS-4V (≤0.1 ppm OH) are compared prior to and after exposure to fast neutron fluences of 1018–5 × 1019 cm–2. The appearance of the IR absorption band of 2260 cm–1 regardless of the large difference in the content of OH groups in nonirradiated KU1 and KS-4V glass is related to the bending vibrations of the bridging ≡Si−O−Si≡ bonds. A decrease in the amplitude of the band at 2260 cm–1 and shift of its maximum by 20 cm–1 to the IR range is caused by the decrease in the bridging ≡Si−O−Si≡ bond angle with the growth of the neutron fluence. The asymmetric band at 3674 cm–1, which is related to OH groups, is observed only in nonirradiated KU1 glass. An increase in the number of OH groups in KU1 glass and the formation of OH groups in KS-4V glass after the accumulation of the neutron fluence of ≥1019 cm–2 rationalizes the slow accumulation of the intrinsic defects such as nonbridging oxygen atoms and oxygen vacancies in both brands of the glass in the range of the neutron fluence.

Influence of the temperature of treatment of KU-1 quartz glass on the value of the elastic recovery of a microindentation imprint

The influence of the treatment temperature of KU-1 quartz glass on the value of the elastic recovery of the microindentation imprint of a Vickers diamond tetrahedral pyramid is studied. It is found that the value of the elastic recovery of the imprint’s diagonal and the fracture resistance of quartz glass upon microindentation varies depending on the preliminary thermal treatment. The obtained experimental results are compared with the data reported by other authors.

Efficiency of generation of optical centers in KS-4V and KU-1 quartz glasses at neutron and gamma irradiation

Pure quartz glasses of KS-4V and KU-1 types are candidates for optical plasma diagnostic system in ITER. The purpose of experiment was to study the efficiency of defect production in these glasses under irradiation with 60Со γ-quanta (5.7Gy/s) dose range of 102–107Gy and the fission reactor neutrons in the fluency range of 1020–1023n/m2 and gammas simulating the plasma influence. In KU-1 (1000ppm OH) the accumulation kinetics of E′-(5.75eV) and NBO-(1.9eV) centers at γ-doses⩾5×105Gy and neutron fluencies <1021n/m2 is faster, than that in KS-4V glasses (<0.1ppm OH) that is caused by rupture of hydrogen bonds. At fluencies >1021n/m2 the NBO accumulation kinetics is slower in KU-1 than in KS-4B, because highly mobile hydrogen atoms access to the generated NBO centers. In KS-4V irradiated to γ-doses102–5×103Gy a new unstable absorption band at 1.8eV was found, which is caused by the glass synthesis conditions and alkali metal impurities. The transparency at 3.5–6.2eV at fluencies 1020–5×1021n/m2 is higher in KS-4V than KU-1. However at fluencies >1021n/m2 in KS-4V the photoluminescence band at 2.7eV is more intensive and distorts a diagnosed signal. The transparency in 3.5–1.2eV at fluencies >1021n/m2 is higher in KU-1 than KS-4V.

Measurements of the refractometric characteristics of optical materials in the 248–5000-nm spectral region

Numerical values have been obtained for the refractive indices of calcium fluoride, KU-1 quartz glass, germanium, silicon, and PO-4 ceramic, used in creating high-resolution photolithographic and aerospace optical systems for the 248–5000-nm spectral region. The results of measurements of the refractive index of a new optical material (Elastosil RT-604A silicone compound) in the 296–1800-nm region are presented. The technique of measuring the characteristics of optical materials in the 248–12 000-nm region is analyzed.

EPR study of gamma and neutron irradiation effects on KU1, KS-4V and Infrasil 301 silica glasses

Electron paramagnetic resonance (EPR) studies have been carried out on KU1 and KS-4V high purity quartz glasses and commercial silica Infrasil 301, irradiated with gamma rays up to a dose of 11.6MGy and neutron fluences of 1021 and 1022n/m2. Gamma irradiations produce a much higher concentration of defect centres (mainly E′, POR and NBOHC) for KU1 and I301 than for KS-4V silica. In contrast, neutron irradiation at the highest fluence produces similar concentrations in all silica types. These results agree to a good extent with those obtained in previous optical absorption measurements. Moreover, oxygen-related centres (POR and NBOHC) have been well characterized by means of electron paramagnetic resonance.

Vacuum ultraviolet excitation spectra of the 1.9 eV luminescence in neutron irradiated KU1 and KS-4V quartz glasses and Infrasil 301

The photoluminescence emission around 1.9 eV, excited from the ultraviolet to vacuum ultraviolet was investigated in neutron irradiated silica (at 1021 and 1022 n/m2 fluences) with different OH and impurity content: KU1 and KS-4V high purity silica and Infrasil 301. The measurements were made at different temperatures from 300K to 10K. The three irradiated silica grades show similar excitation spectra shape, although the band intensities are different depending on silica grade and temperature. Neutron irradiated KU1, with the highest OH content, shows the highest red emission attributed to nonbridging oxygen hole centers (NBOHCs). The excitation profile, from 4.0 to 8.8 eV, has two bands, which are centered around 4.85 eV and 6.5 eV. The band intensities increase with decreasing temperature from 300 to 10K for the three types of silica.

Discrete conical emission rings observed upon filamentation of a femtosecond laser pulse in quartz

Supercontinuum emission observed upon filamentation of transform-limited collimated femtosecond laser pulses in a transparent condensed medium (fused KU-1 quartz) is studied experimentally and numerically. The splitting of diverging conical supercontinuum emission into discrete rings was observed with increasing the pulse energy.

Neutron irradiation effects on optical absorption of KU1 and KS-4V quartz glasses and Infrasil 301

In this work we have compared the effects of neutron (10 21–10 22 n/m 2 fluences) and gamma irradiation (23.8 MGy dose) on the IR–vis–UV optical absorption spectra of high purity silica with different OH content: KU1 (∼800 ppm), KS-4V (<0.2 ppm), and commercial silica Infrasil 301 (<8 ppm). The results show that the UV–vis optical degradation of the silica, after neutron irradiation at the highest fluence is similar for the three grades studied, while gamma-induced optical absorption depends on the material grade (KS-4V shows the lowest optical absorption). The effects of both types of radiation on the IR band related with the hydroxyl group (3650 cm −1) depend on the silica grade. For KU1, the shape of this band changes with neutron fluence. For Infrasil 301 gamma and neutron irradiated, this band height increases, possibly due to free molecular or hydrogen atoms. The shift to lower energies observed for the 2260 cm −1 band in the three neutron irradiated silica grades, reflects the changes induced by neutrons in the lattice bonding angle distribution.

Radiation induced absorption and luminescence of selected alternative radiation resistant glasses

Two types of multicomponent glasses, 75% SiO 2: Na, Ca, one 0.05% Ce doped, have been studied in terms of radioluminescence, radiation induced optical absorption, and photoluminescence. The samples were irradiated with 1.8 MeV electrons at different temperatures and dose rates. During irradiation radioluminescence and optical absorption measurements were performed at different doses. The results show that both types of glasses are highly sensitive to radiation damage. For irradiation at 200 °C, some improvement is observed, but the behaviour of these glasses is worse than for KU1 quartz glass.

Thermal stability of neutron irradiation effects on KU1 fused silica

Optical absorption spectra of neutron irradiated (1021n/m2 and 1022n/m2) KU1 quartz glass samples have been measured. The effects of post-irradiation isochronal thermal annealing, up to 850°C, have been investigated. The general effect of the isochronal annealing is a decrease in the optical absorption bands as the temperature increases. Optical absorption bands have been identified with known defects from the literature, and their concentration temperature dependence has been analyzed. While the annealing curves of the E′ and non-bridging oxygen hole centres (NBOHC) are similar, that corresponding to oxygen deficiency centres (ODC(II)) is quite different suggesting that the recombination of E′ and NBOHC is part of the same process whereas the recombination of ODC is controlled by the presence of another undetected defect.

Radiation resistance of optical materials for windows of UV and VUV excimer lasers

The behaviour of modern quartz glasses and fluo-rite is studied experimentally under a prolonged action of the 280-keV electron beam pulses and an overall fluence of up to ∼30 kJ cm-2. The induced absorption in all investigated mate-rials saturates with increasing the fluence. The maximum variation of transmission in high-purity CaF2 samples does not exceed 5%–10% in the wavelength range 120–1000 nm. Quasi-stationary absorption in the region of ∼180–300 nm in the KS-4V quartz glass sample is approximately four times smaller than that in the KU-1 quartz glass and half the value for Corning 7980 glasses.

Radioluminescence behaviour for electron irradiated KS-4V

KS-4V, a low OH silica, is being considered for use in different fusion applications such as diagnostic windows and remote handling optical transmission components. For these applications radioluminescence (RL) is an important issue. A systematic study of RL as a function of temperature, dose rate and dose has been made using 1.8 MeV electron irradiations. The behaviour has been compared with KU1 quartz glass (high OH content) and the results indicate that KU1 is much better than KS-4V in terms of RL. Intense RL bands associated with self trapped excitons are observed for KS-4V but not for KU1. Furthermore the KS-4V RL exhibits a complex dependence on irradiation temperature, however the RL intensity decreases with irradiation dose.